This R01 project builds on a highly successful R21 project which involved the development and feasibility of a Minimally Invasive Neurosurgical Intracranial Robot (MINIR-I) using shape memory alloy (SMA) actuators as well as the evaluation of the device under continuous MRI for resection of an implanted metastatic tumor in swine brain. While we achieved the specific aims of the R21 project, we also discovered new challenges, which are the basis for this R01 application. Brain tumors are among the most feared complications of cancer occurring in 20-40% of adult cancer patients. Despite numerous advances in treatment, the prognosis for these patients is poor, with a median survival of 4-8 months. Whether a primary (intrinsic) malignancy, or a secondary (metastatic) malignancy, involvement of the brain in a cancer patient is devastating, because it threatens the very personality and identity of the individual, and is invariably the most likely of all complications o directly and severely affect the quality of life. Currently, the optimal treatment for most brain tumors involves primary surgical resection to facilitate adjuvant therapies such as radiation and chemotherapy. Unfortunately, many patients cannot undergo primary surgical resection of their brain tumor due to unfavorable location of the lesion (usually deep or otherwise inaccessible to conventional neurosurgical techniques), and poor general health of the patient. To address this problem, based on the success of our R21 pilot project, and the lessons learned therein, we propose to develop a fully MRI- compatible MINIR-II and demonstrate the safety and efficacy of MINIR-II through comprehensive assessments on clinically relevant ex vivo and in vivo swine and followed by human cadaver models. As envisioned, MINIR-II will be under the direct control of the physician, with targeting information obtained exclusively from real-time MRI that uses active targeting methods with the sensors embedded within MINIR-II. To realize MINIR-II, we will address four specific aims: 1) Design a fully MRI compatible multiple degree-of-freedom (DOF) MINIR-II of rigid plastic body with cable driven joints, hollow inner core for routing cablin and electronics, irrigation and suction capability, and tumor removal capability, 2) Develop and characterize a multi-piece mold capable of molding geometrically complex robot links with miniature features to produce a completely disposable/single use MINIR-II prototype, 3) Develop a tracking and navigation system for MINIR-II that will allow visualization of proximal and distal structures for accurate targeting and resection of the tumor, and finally 4) the safety and efficacy of MINIR-II in gelatin phantoms and clinically relevant models of metastatic brain tumor including, a cadaveric pig model, a live pig model, and a human cadaver model. Our goal at the end of this project is to have MINIR-II (operated under continuous MRI) ready for clinical trials.